Ambulatory medical devices, such as medication delivery devices, or infusion pumps, are designed and implemented to operate reliably over long periods to assure patient safety. To satisfy this requirement, it is common practice to build some “redundancy” into the device in order to eliminate single-point failure modes. For example, in some such devices intended to deliver a certain therapy to a patient, e.g., medication, it is known to incorporate two or more microprocessors (which term, as used herein, is intended to encompass microcontrollers) configured to independently perform duplicate functions. For example, note U.S. Pat. No. 6,648,821 which describes:                An implantable infusion pump possesses operational functionality that is, at least in part, controlled by software operating in two processor ICs which are configured to perform some different and some duplicate functions. The pump exchanges messages with an external device via telemetry. Each processor controls a different part of the drug infusion mechanism such that both processors must agree on the appropriateness of drug delivery for infusion to occur.        